<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <style>
        /* 语法
        选择器1 选择器2 {}

        选择器2 需要在选择器1 的内部才可以生效
        儿子, 孙子, 子子孙孙都是可以的
         */
        /* div 内部的 span */
        div span {
            background-color: skyblue;
        }

        /* div 里面的 .last */
        div .last {
            color: yellowgreen;
        }
    </style>
    <title>Document</title>
</head>
<body>
    <span> span 标签</span>
    <div>
        <span>这是 div 的儿子 span</span>
    </div>
    <div>
        <p>
            Lorem ipsum dolor sit amet consectetur adipisicing elit. Rem quo nesciunt amet voluptatem, expedita, modi ad fugit aperiam architecto nulla illo iusto provident eaque id ipsa fuga aspernatur <span class="last">incidunt</span> illum.
        </p>
    </div>
</body>
</html>